<!DOCTYPE html>
<style>
div {
  width: 50px;
  height: 100px;
  border: 1px solid gray;
  display: inline-block;
  writing-mode: vertical-rl;
}
</style>
<!-- dir="rtl" should make the text bottom-aligned (i.e. line-right) -->
<div dir="rtl">x</div>
